huntingtons chorea, GCA, temporal arteritis Flashcards
what is huntingtons chorea
Neurodegenerative disease caused by malfunction in huntington gene (CAG repeats). causes neuronal cell atrophy - loss of GABA-neurgic neruones in caudate nucleus and putamen of basal ganglia
LESS GABA MORE DOPAMINE INCREASED MOVEMENT
pathophysciology of huntingtons chorea
36 or more CAG triplet repeats - huntingtons protein build up in striatum - cell death - (STRIATUM ATROPHY)
loss of GABAnergic neurones in caudate nucleus and putamen of basal ganglia
less GABA = Dopamine no as regulated so increased to striatum = INCREASE MOVEMENT
GABA = a neurotransmitter inhibitor
CFs of huntingtons chorea
prodromal phase - mild phsycotic and behavioural sympotoms (Depression personality chagne iritability)
late symptoms - chorea (explosive jerky movements) - hyperkinesia
rigidity
dysarthria
dysphagia
dementia
abnormal eye movemetns
DDx of huntigtons chorea
wilsons
sle
LEVODOPA (parkinsons treatment to decrease GABA - too much decrease = other way)
Dx of huntingtons chorea
genetic testing (over 35 cag repeats) MRI - striatum atrophy
Mx of huntingtons chorea
no tx to prevent prgoression
COUNSELLING - to patient and children (as ANTICIPATION)
BDZs = benzodiazepines - increase GABA effect
tetrabenazine - for chorea - depletes dopamine
risperidone - antiphyschotic
SSRI setraline - antidepress
VALPROIC ACID - anti convulsant - increases GABA
Huntington’s genetic features
Autosomal dominant
100% penetrance,
gets more and more repreats with every generation - starting earlier (anticipation)
= at least 36 CAG repeats
Giant cell arteritis
granulomatous inflamation of bv wall (vasculitis) of temporal artery
what is giant cell arteritis assos with
polymyalgia rheumatica (50%)
epid of GCA
most common type of vasculitis in the elderly
What are the symptoms of GCA?
Temporal pulsating headache Scalp tenderness Jaw claudication Amaurosis fugax Systemic: fatigue, fever, myalgia, (WL, depression)
How is GCA investigated?
Pulseless temporal artery
Raised ESR and CRP
Biopsy within 1 week (skip lesions)
What is the treatment of GCA?
Prednisolone 12 months
Visual symptoms - IV methylprednisolone 3 days
PPIs and bisphosphonates from long term steroid use
What condition presents in 50% GCA patients?
Polymyalgia rheumatica
What is temporal arteritis?
Inflammatory granulomatous vasculitis of large cerebral arteries
sign of GCA
palpable tender non pulsatile temporal artery
thickened
why get amaroux fugax in GCA
extensitioin of the vasulitis to the opthalmic artery
DDx of GCA
migraine
tension headache
trigeminal neuralgia
polyarteritis nodosa
Dx of GCA
bloods - high ESR/CRP
temporal artery biopsy *** - necrotising, skip lesions (within a weeK)
What is trigeminal neuralgia?
Paroxysms of intense, debilitating pain in the distribution of the trigeminal nerve (CN5)
what does the trigem nerve split into
- 1 - opthalmic
- 2 - maxillary
- 3 - mandibular
what is the moto fuction of CN5
trigeminal = muscles of mastication
RF of trigeminal neuralgia
HTN
What is the peak age of onset of trigeminal neuralgia?
50 years
What causes the pain in trigeminal neuralgia?
Compression of the trigeminal nerve causing demyelination and excitation of the nerve = PAIN
What are the characteristics of trigeminal neuralgia?
Sudden, unilateral paroxysms of knife-like/electric shock pain
Mandibular –> maxillary and ophthalmic
Lasts seconds to minutes
Triggers- eating, shaving, talking
Trigeminal neuralgia Causes
Primary idiopathic.
relating to age
secondary: skull abnormality, malignancy, MS
How is trigeminal neuralgia diagnosed?
MRI to exclude secondary causes or other pathologies
What is the treatment of trigeminal neuralgia?
Carbamazepine - membrane stabalizer = less freq impulses (antiepilpetic aswell = tonic-clonic and partial seizures)
Neurovascular decompression
